14.3.2023 CSMANTECH-2023-Kevin-Pikul-Extended-Abstract

7.2.3.2024 1.6 μm Lasing and Mid-Wave Infrared Detection in InP-Based Transistor-Injected

2B.2 Final.2025

In this work, impurity-induced disordering by Zn diffusion is proposed as a method for lateral current confinement in InP-based quantum cascade lasers. This method improves current confinement for a shallow ridge-guide laser bar while preserving material for lateral thermal dissipation and avoiding an increase of optical loss. Using ZnAs2 solid source, the diffusion profiles and rates in an InGaAs/InAlAs superlattice is characterized. A diffusion coefficient of 7.35×10-12 cm2/s is extracted for a 550 ºC process. Zn-driven impurity-induced disordering of an InGaAs/InAlAs superlattice is experimentally demonstrated. Two-terminal electrical modeling is performed to verify improved confinement of the injected electrons. Furthermore, analysis of the optical mode is performed to determine the best mask and diffusion parameters. Optical modeling results indicate feasible diffusion profiles with a decrease in waveguide loss (from 13.041 cm-1 to 12.77 cm-1) and minimal change in gain overlap (51.15% to 51.13%). Finally, quantum cascade material is processed and electrically characterized with initial indications of a reduction of lateral current spreading by 61%.

6B.2 Final.2025

A novel long wavelength 1550 nm VCSEL structure is introduced utilizing an InP-based substrate and bottom DBR mirror, a dielectric silicon/silicon dioxide top DBR mirror, and a tunable phase-matching layer fabricated from a piezo-electric/electro-optic material. By applying a voltage bias across this phase-matching layer, the layer’s optical thickness can be altered, thereby shifting the overlap of the electric-field standing-wave pattern with
the gain region. When process variation/nonuniformity negatively impact the device performance, mainly threshold current and threshold modal gain, tuning of the
phase matching layer can optimize the standing wave overlap with the gain region, minimizing threshold current and modal gain. This work presents the novel
epitaxial structure designed and explores the viability of various materials for application as the phase-matching layer via simulation results utilizing the transfer-matrix method.

10A.4 Final.2025

2D-VCSEL arrays utilizing elliptical disorder-defined apertures for simultaneous single-mode, singlepolarization operation are demonstrated. Optical losses induced by the disordered region in the periphery of the VCSEL suppress the capability of higher-order modes from lasing, achieving single-fundamental mode
operation. Furthermore, introducing eccentricity to the aperture creates an asymmetric threshold gain, or dichroism, that selectively suppresses one of the two polarization states inherent to VCSELs, resulting in single-polarization operation. The work presented here discusses the design, fabrication, and characterization results of the 2D-VCSEL arrays. The arrays are characterized for optical output power, single-mode performance via optical spectra measurements, and single-polarization performance via polarization-resolved light-current-voltage (PR-LIV) curves.